This double blind pharmacotherapy research is designed to determine the efficacy of imipramine in comparison to methylphenidate in the treatment of hyperactive children. The initial comprehensive and multidisciplinary diagnostic evaluation serves to delineate and to classify the types of hyperactive children. The effects of the drugs on pediatric, psychological, and psychiatric variables will be studied to determine the indications for specific pharmacotherapeutic agents for the different categories of hyperactive children. We plan to continue the pharmacotherapy, and study the long term efficacy of medications and determine the long term clinical course of treated hyperactive children.